solve for x,y

solve for x,y

x2+y(x+1)=17 and

y2+x(y+1)=13

3 Answers

1
ARKA(REEK) ·

Subtracting (1) from (2) .....

=x2-y2+y-x=4

=(x-y)(x+y-1)=4

Now this can either be ......

=(x-y)(x+y-1)=2*2

or, (x-y)(x+y-1)=4*1 or, (x-y)(x+y-1)=1*4

By solving .....

x,y=(2.5,0.5), (3,-1), (3,2)

106
Asish Mahapatra ·

@arka .. that is definitely NOT the case.. u can break 4 into infinitely many ways...

add both equations. we get
(x+y)2 + (x+y) = 30
taking x+y = t, we get

t2 +t -30 = 0
=> t = 5, -6

=> x+y = 5, -6

CASE I, x+y = 5
subtract both equations,
(x+y)(x-y) - (x-y) = 4
=> 4(x-y) = 4
=> x-y = 1 and x+y = 5
solving we get x = 3, y = 2

CASE II, x+y = -6
subtracting both equations,
(x+y)(x-y) - (x-y) = 4
=> -7(x-y) = 4
=> x-y = -4/7 and x+y = -6

=> x = -23/7 and y = -19/7

just hope there arent any calculation errors

1
ARKA(REEK) ·

Yes u r absolutely right.

Sorry ........ I just considered the equation to be the product of 2 integers.

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